The present invention relates to novel compositions for application to synthetic polymeric materials to improve the wettability characteristics of the materials such that when the materials are utilized in the manufacture of laminates or composites, improved products result. The invention further relates to the synthetic polymeric materials coated with the chemical composition and to composites produced therefrom.
In recent years, structural composite materials have been produced suitable for use in replacing metallic structural elements in wide and various industries, stemming from both building structures to high tech applications such as aircraft, space vehicles, and the like. In general, such structural composite materials have included the reinforcement of a polymeric matrix with various forms of filamentary or fibrous materials such as glass fibers and filaments, carbonized fibers and filaments and the like. While such structural materials have been successfully employed, the two types referred to above are fraught with certain disadvantages. For example, the structural composites reinforced with carbonized fibers have historically been quite expensive, while the composites that include glass fibers or filaments experience certain strength or other problems. Particularly, insofar as glass reinforced composites are concerned, while the composites are adequate in tensile and compressive strength, the impact resistance of the structure is less than desired. In fact, in order to achieve a desired impact resistance, oftentimes the ultimate laminate size of the composite exceeds the dimensional requisites for the structure. Also, fragility of glass limits the processes in which the composites are made to those where the glass fabrics or materials are not broken.
It is also presently known that stiffness of a composite structure is achieved by mere contact between the polymer matrix and the reinforcing material. Ultimate strength of the composite is, however, dictated by the bond strength between the particular polymer matrix and the reinforcing material. In this vein, whereas it is likewise known that synthetic polymeric materials such as polyester, polypropylene, nylon, and the like possess impact strength characteristics exceeding those of the similar glass materials, successful utilization of such materials in a structural composite has heretofore proved generally unsuccessful. Such synthetic polymeric materials experience poor wettability by the polymer matrix being utilized, particularly unsaturated polyester resin syrups, whereby bond strength between the matrix and the reinforcing material is also poor. In the case of an epoxy matrix, certain coupler compounds such as silanes have been utilized, particularly in connection with glass reinforcing materials. With the saturated polyester syrup matrices, however, while same will suitably bond to glass, problems have been experienced in achieving proper bonds with synthetic polymeric materials such as the polyesters, polypropylenes, and the like.
Not only has the desirability of composite structures containing polyester or other types of synthetic reinforcing materials thus been realized, but in recent years, significant development effort has been expended towards pretreatment of synthetic polymeric materials to render same suitable for use in structural composites. Allied Fibers Division of Allied Corporation, for example, has pretreated polyester and nylon fibers with plastics overfinishes which are stated to improve the suitability of such fibers as reinforcing materials in structural composites. The Allied fibers are marketed under the trademark COMPET, which are stated to provide ample strength and a very high degree of toughness. Furthermore, plastic materials reinforced with COMPET fibers are stated to be resistant to impact, abrasion and fatigue.
While the composition applied to the COMPET fibers is unknown, it is believed that the subject matter of the present invention represents patentable improvement thereover. Particulary improved physical characteristics are achieved with composites produced from the synthetic materials treated according to teachings of the present invention compared to test results of composites utilizing the COMPET fibers. Further, as to the present invention, utilizing the novel composition taught hereby, pretreated synthetic polymeric materials may now be properly wetted out by polymer matrices for the formation of a strong bond therebetween. Composites produced therefrom exhibit improved physical properties over presently known composites.
There is no known prior art that is believed to anticipate or suggest the subject matter of the present invention.